Machines of this kind are known from DE 198 247 98 (U.S Pat. No. 6,340,130).
A width of foil is rolled off of a supply roll, turned around a stationary deflection roll and a dancer roll that is supported in a way that allows it to move, and forwarded by a take-off device. From this it is also known to use two dancer rolls that are securely coupled to one another. The dancer roll serves to regulate the unrolling of the width of foil from the supply roll.
The weight of the dancer rolls places a load on the width of foil in this connection and consequently stretches it, which has proven to be detrimental. The weight of the dancer roll can be considerable. This is particularly detrimental in the processing of thin foils, which, for example, because of their elasticity properties or their stretching capability, withstand only limited tensile stress. Furthermore, it has proven to be detrimental that the dancer rolls move only by jerks and jolts, which results in uncontrolled tensile stress and thereby in uncontrolled stretching of the foil. This is particularly detrimental in the manufacture of foil bags, in which case the foils are processed with precisely specified lengths.